SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8e7401399bd52632309d6d61c3d32888b9d6f6f6a94204e1e1ed441761926903' 
  AND token = 'UCzPgfcVkpAcBdDPcVgdWgzige44iQSLLDomuVsJRb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}